In database or file accessing, computer based recognition of query strings often relies on mapping or matching of an input query string with a term from a set of stored terms. Indefinite query strings, such as for example those containing misspelled terms, are mapped only if the misspelled term is also stored. The misspelled term can be replaced with the correct spelling before mapping, or the misspelled term can be included in the term set to allow its mapping. Out of practicality, however, only the most common misspellings of selected terms can be stored and recognized for matching. Thus, uncommon misspellings of terms can go unrecognized even if they are only slight errors, and improved query string matching can increase the relevance of database and file accessing and/or searching.